Documentation

Documentation & guides

Everything you need to know about StringsTheory products — setup guides, feature docs, and reference.

Getting Started with INV

New to StringsTheory INV? Start here. Install, activate, and set up your first inventory in minutes.

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Support & FAQ

Frequently asked questions across all products, contact info, and app descriptions.

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Contact Us

Can't find what you need? Send us a message and we'll help you get sorted.

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Inventory

Work order, inventory, and production management for repair shops, luthiers, and small manufacturers.

Inventory
Inventory Management
Items, SKUs, categories, photos, barcodes, and more
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Work Orders
Work Orders
Creating orders, templates, checklists, PDFs, and emails
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Customers
Customer Management
Customer records, CSV import, and work order history
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Manufacturing
Bill of Materials
Assemblies, component costs, and BOM-linked work orders
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Serialized Items & Production
Serial tracking, production orders, bulk edit, and CSV import
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COGS Reports
Revenue, costs, margins, and transaction ledger
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Labels & Printing
Label Design & Printing
Label designer, Dymo templates, and field placeholders
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Print Queue & Network Printing
Queue management, network printers, and batch printing
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Integrations Annual
Integrations
Square, Google Sheets, Shopify — setup and sync
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Cloud & Team Annual
Cloud Sync & Multi-Device
Offline-first sync, conflict resolution, and web app
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Team & Multi-User
Roles, invites, user management
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Data Management
Bulk Operations & CSV
Multi-select, bulk edit, CSV import/export workflows
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Backup & Restore
Scheduled backups, restore, and data export
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Configuration
Settings & Configuration
Categories, SKU format, labels, branding, email, and language
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Plans & Billing
Monthly vs Annual, trials, upgrades, and cancellation
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Platform Support
macOS, iPad, web app, and auto-updates
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Tech Tools

15 precision tools for tube amp builders, technicians, and guitar techs. Mac, iPad, and iPhone.

Calculators
Bias Calculator
Three measurement modes (dissipation limits, cathode resistor, direct), 60+ tube types, real-time dissipation gauge, Class A/AB/cathode reference tables
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Resistance, Capacitance & RC Filter
Series/parallel calculators, color band decoder, voltage divider with load, ceramic cap codes, low/high-pass cutoff frequency with circuit schematics
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LED & Speaker Calculators
LED resistor calculator with forward voltage reference. Speaker cabinet impedance with series, parallel, series-parallel wiring and Celestion-style diagrams
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String Tension Calculator
Guitar and bass (4-8 strings), multi-scale fanned fret support, custom string packs, lb/kg/N conversion
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References & Tools
Tube Data & Rectifier Reference
607+ tubes with pinout diagrams, max ratings, and substitutes. Rectifier comparison with datasheet-verified max filter cap values
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Chromatic Strobe Tuner
McLeod NSDF pitch detection, phase-based strobe animation, needle gauge mode, 432/440/442/444 Hz reference pitch
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Code Decoders
EIA manufacturer codes, Fender serial/amp dating, Gibson serial decoder, Marshall dating, reverb tank decoder, potentiometer date codes
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Design

Tube amplifier circuit analysis toolkit with 5 integrated tools. Mac and iPad.

Circuit Analysis
Tonestack Calculator
53 tone circuit models across 9 categories. Real-time Bode plots, adjustable pot tapers, multi-circuit comparison, oscilloscope view
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PSU Designer
Time-domain power supply simulation with 173 rectifier models. Full-wave CT, bridge, voltage doubler, half-wave. PSUD2-compatible .psu format
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Load Lines
Plate characteristic curves with Koren models for ~50 tubes. Single-ended and push-pull, draggable Q-point, power dissipation overlay
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Reference & Planning
Tube Data (3,727 tubes)
Pinout diagrams, max ratings, operating conditions, substitutes. 90 rectifier tubes with datasheet-verified max filter cap values
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Build Planner
479 amp references across 30 manufacturers. Heater rails, B+ requirements, mains fuse sizing, transformer matching (Hammond, Edcor, Mercury Magnetics, Pacific)
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In-App Help System
67 searchable articles, step-by-step guides, worked examples, safety warnings, 30-term glossary
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Print Server

Dedicated hardware unit that makes all your USB thermal printers wireless and smart. Coming soon.

Features
Multi-Printer Management
Connect 1-6+ printers, assign nicknames and roles, Twin Turbo dual-spool support, automatic USB discovery
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Smart Routing & Label Stocks
Route by name, role, or label size. 80+ built-in label stocks across Dymo, Brother, Zebra, and Rollo. Load balancing across matching printers
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Supported Printers & Protocols
Dymo, Brother, Zebra, Rollo via USB. AirPrint (iOS/Mac), Mopria (Android), SMB (Windows), REST API. No client drivers needed
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Specifications & Setup
Plug in, connect to network, assign roles, print. 24/7 unattended operation, automatic updates with rollback
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